1. Field of the Invention
The present invention relates to polypeptides having endopeptidase activity and to methods of producing and using the polypeptides. The invention also relates to methods of making a protein hydrolysate such as a food protein hydrolysate.
2. Description of the Related Art
Trypsin (EC 3.4.21.4) is a serine protease found in the digestive system of many vertebrates, where it hydrolyses proteins. Trypsin cleaves peptide chains mainly at the carboxyl side of the amino acids lysine and arginine. Trypsin is available in high quantity in pancreas, and can be purified rather easily. Hence it has been used widely in various biotechnological processes. Trypsin is used in baby food to pre-digest it. It can break down the protein molecules, which helps the baby to digest it, as its stomach is not sufficiently developed to digest bigger protein molecules. Trypsin can be used to break down milk proteins to provide a partial milk protein hydrolysate for infant formulae. For example, WO93/04593 and U.S. Pat. No. 5,039,532 disclose use of pancreatic trypsin preparations for the production of hypoallergenic whey protein hydrolysates.
For several reasons, in the production of food and, in particular, in the production of baby food or infant formulae, use of proteolytic enzymes derived from a microorganism, such as a bacterium, may confer benefits. For example, production of bacterial enzymes can be easily optimized to be efficient and easy to control. Therefore, such enzymes can be produced in large quantities and at high purity. Also, use of a microbial enzyme will help overcoming increasing Quality Assurance related difficulties as regards extraction of enzymes from an animal source.
One object of the present invention has been to provide novel microbial proteases for potential use, e.g., in the food industry.